Dual-mode nozzle assembly with passive tip cooling

Abstract

A flame-holding nozzle for a combustion turbine engine is disclosed. The nozzle includes several elongated sleeves in a substantially concentric arrangement. The sleeves cooperatively provide distinct passageways for fluids to move through the nozzle. The nozzle includes conduits that advantageously direct fluids to designated regions of the nozzle, allowing fuel and cooling fluid to move within the nozzle without becoming commingled. Portions of the nozzle sleeves are also strategically arranged to transmit fluids in a manner that provides substantially-uniform thermal expansion, thereby reducing the need for sliding joints or bellows arrangements.

What is claimed is:  
     
       1. A dual-mode fuel nozzle for a combustion engine, said nozzle comprising: 
       an elongated first sleeve characterized by an upstream end and an opposite downstream end;  
       a supplemental sleeve disposed radially inward of said first sleeve, said first and supplemental sleeves defining a first fuel passageway therebetween, said first fuel passageway including an inlet and an exit, said inlet being adapted for fluid communication with a source of fuel;  
       a second sleeve disposed radially inward of said supplemental sleeve said supplemental and second sleeves defining a supplemental fuel passageway therebetween, said supplemental fuel passageway including an inlet and an exit, said an inlet being adapted for fluid communication with a source of fuel;  
       a third sleeve disposed radially inward of said second sleeve, said second and third sleeves defining a cooling fluid passageway therebetween, said cooling fluid passageway having an inlet and an exit; and  
       a cooling fluid conduit adapted to fluidly connect said cooling fluid passageway with a source of cooling fluid, said conduit having a conduit entrance located upstream of said fuel passageway exit and a conduit exit in fluid communication with said cooling fluid passageway inlet,  
       whereby said cooling fluid conduit, said cooling fluid passageway, and said fuel passageways cooperatively ensure that cooling fluid passing through said cooling fluid passageway exit is substantially fuel-free during operation.  
     
     
       2. The dual-mode fuel nozzle of  claim 1 , wherein said cooling fluid is air discharged from a compressor operatively associated with said combustion engine. 
     
     
       3. The dual-mode fuel nozzle of  claim 1 , wherein said first sleeve cooperatively forms an outer passageway with an outer boundary member spaced radially outward from said first sleeve, said outer passageway being in fluid communication with said fuel passageway exit, said outer passageway including an upstream entrance and a downstream exit, said entrance being adapted for fluid communication with a source of air. 
     
     
       4. The dual-mode fuel nozzle of  claim 3 , wherein said outer boundary member is an outer wall disposed around a portion of said first sleeve. 
     
     
       5. The dual-mode fuel nozzle of  claim 3 , further including a mixing member disposed within said outer passageway, said mixing member being adapted to at least partially produce a pressure drop. 
     
     
       6. The dual-mode fuel nozzle of  claim 3 , wherein said cooling fluid is motivated through said cooling fluid passageway substantially by a pressure drop between said cooling fluid conduit entrance and said cooling fluid exit. 
     
     
       7. The dual-mode fuel nozzle of  claim 6 , wherein said cooling fluid includes air discharged from a compressor operatively associated with said combustion engine. 
     
     
       8. The dual-mode fuel nozzle of  claim 3 , wherein said cooling fluid is motivated by a pressure drop at least partially induced by a mixing member disposed within said outer passageway. 
     
     
       9. The dual-mode fuel nozzle of  claim 3 , wherein said cooling fluid is motivated by a pressure drop at least partially induced by orientation of an outer wall with respect to said first sleeve. 
     
     
       10. The dual-mode fuel nozzle of  claim 9 , wherein said pressure drop is at least partially induced by a mixing member disposed within said outer passageway. 
     
     
       11. The dual-mode fuel nozzle of  claim 3 , wherein: 
       said first sleeve and said second sleeve are each characterized by a first surface and an opposite second surface, each of said first surfaces being arranged for contact with a first fluid having a first temperature and each of said second surfaces being arranged for contact with a second fluid having a second temperature, wherein said contact produces substantially-equal thermal expansion in said first and second sleeves.  
     
     
       12. The dual-mode fuel nozzle of  claim 11 , wherein: 
       said first and second sleeves are joined together in a rigid relationship, whereby said substantially-equal thermal expansion facilitates said rigid relationship.  
     
     
       13. The dual-mode fuel nozzle of  claim 3  further comprising a bellows member disposed within said supplemental sleeve. 
     
     
       14. The dual-mode fuel nozzle of  claim 3  further comprising a mounting flange adjacent an upstream end of said nozzle, said cooling fluid conduit being disposed in said mounting flange. 
     
     
       15. The dual-mode fuel nozzle of  claim 14  wherein said cooling fluid conduit is oriented in a substantially-radial relationship with respect to a longitudinal axis of said nozzle. 
     
     
       16. The dual-mode fuel nozzle of  claim 3  further comprising a fluid transfer member adjacent an upstream end of said nozzle, said cooling fluid conduit being disposed in said fluid transfer member. 
     
     
       17. The dual-mode fuel nozzle of  claim 16  wherein said cooling fluid conduit is oriented in a substantially-radial relationship with respect to a longitudinal axis of said nozzle.